Ovicides

ABSTRACT

It has been found that substituted aminoacetonitriles of the structure ##STR1## wherein X and Y, independently, stand for hydrogen, halogen, loweralkyl, loweralkyloxy, nitro or CF 3  ; R is hydrogen or methyl; and R&#39; is hydrogen or loweralkyl are excellent insect ovicides.

DETAILED DESCRIPTION OF THE INVENTION

Some substituted aminoacetonitriles have been known to be usesfulintermediates for certain drugs or for the preparation of heterocycliccompounds. It has now been found that particular compounds of thisseries have unique ovicidal activity.

The present invention is directed to the process of preventingmaturation of eggs of crop-damaging insects, consisting essentially inapplying to the habitat of said eggs an ovicidal amount of a compound ofthe formula ##STR2## wherein X and Y independently represent hydrogen,loweralkyl, loweralkyloxy, halogen, nitro or trifluoromethyl; R ishydrogen or methyl; and R' is hydrogen or loweralkyl; and simple acidaddition salts thereof, together with an agriculturally acceptablediluent. The above reference to "loweralkyl" is meant to include thosealkyl groups that contain 1-4 carbon atoms. Most of the compounds usedin the present invention are known since 1954 (Marxer; Helv. Chim. Acta,37, 166) when it was disclosed that they are useful as intermediates fordrugs.

Among the agriculturally acceptable diluents, water is the mostconvenient one, although water is seldom used alone since detergents,wetting agents and the like are often necessary or desirable to providea more homogeneous solution or dispersion of the active material. Soliddiluents are often more suitable than liquids, as storing, shipping andpackaging is easier than with liquid products.

The compounds of the current invention may be applied in the form ofemulsifiable concentrates, powders, granules or dusts. An agronomicallyacceptable carrier for the purposes of this invention includes anysubstance which can be used to dissolve, disperse or diffuse the abovenovel compounds, without impairing the effectiveness of the activeingredient, and which is not deleterious to the soil or the plant in anychemical or physical manner. Particularly favored compositions are thosewherein the active ingredient is present in a range from 1-20% by weightand the mixture of active compound and the diluent form awater-emulsifyable concentrate or it is a wettable powder. Soliddiluents of this nature are well known in the agricultural formulationart. They include clay, diatomaceous earth, bentonite, silica, etc.

In formulating the composition of this invention, other components maybe included to aid in the adsorption or absorption of the activeingredients by the plant. Components such as wetting agents,solubilizers, emulsifiers, humiditants, surfactants and other adjuvantsuseful for this purpose may be incorporated in the formulations.

The above compounds are preferably compounded with inert diluents to aliquid or solid composition containing between 10,000 and 200,000 ppm,particularly compositions containing 25,000 to 50,000 ppm. Such stockmixes are easily packaged and stable and can be diluted by the consumerto the necessary concentrations of between 500 to 2,500 ppm.

The compounds of the present invention can be made by the well knownStrecker reaction, a condensation of a cyanide salt with an aldehyde orketone and the aniline or N-methylaniline carrying the requiredsubstituents X and Y.

In order to illustrate specific embodiments of the present invention,reference is made to the following examples, which, however, are notintended to limit the scope of this invention. In all of these examples,the microanalyses of the produced compounds were found to be inexcellent agreement with the expected calculated values for theseproducts.

EXAMPLES 1-18

The compounds of Formula I wherein R and R' both are hydrogen were allmade by the detailed description of the above Marxer reference. Theirphysical characteristics are given below in °C. in Table I:

                  TABLE I                                                         ______________________________________                                        Compound #  X         Y        Boiling Point                                  ______________________________________                                        1           H         H        63°/11 mm                               2           2-Cl      H        127-8°/0.05 mm                          3           4-Cl      H        m.p. 63-4°                              4           3-Cl      H        140-50°/0.5 mm                          5           3-Br      H        165-70°/2 mm                            6           3-Me      H        140-50°/5 mm                            7           4-Me      H        160-70°/10 mm                           8           3-CF.sub.3                                                                              H        120-30°/1 mm                            9           4-MeO     H        m.p. 74-6°                              10          4-NO.sub.2                                                                              H        m.p. 112-3°                             11          3-Cl      4-Cl     m.p. 90-1°                              12          2-Me      4-Me     140°/1 mm                               13          2-Me      4-Me     m.p. 55-7°                              14          2-Me      4-Cl     m.p. 88-90°                             15          2-MeO     H        m.p. 70.5-2°                            16          2-Cl      5-Cl     m.p. 96-9°                              17          2-Cl      4-Cl     m.p. 73-5°                              18          3-NO.sub.2                                                                              H        m.p. 100.5-1.5°                         ______________________________________                                    

By replacing the paraformaldehyde used for making the above compoundswith acetaldehyde or butyraldehyde, the analogs of the above compoundsare obtained wherein R' is methyl or propyl, respectively.

Using the N-methyl analogs of the aniline derivatives needed for thepreparation of the above compounds produces the corresponding homologswith R being methyl. In some instances, the condensation reactionrequires a few extra hours at elevated temperature to obtain theexpected good yields which, in the above instances, range from 50-85% oftheory.

EXAMPLE 19

Fresh strips are taken from an appropriate cage of young adult cabbageloopers. This strip is disinfected for 10 minutes in a 10% formaldehydesolution. This step is necessary to surface sterilize the eggs toprevent extraneous mortality to newly emerged larvae from viruses andother pathogens. After treatment in the formaldehyde solution, eggstrips are rinsed in running tap water for thirty minutes and thenallowed to air dry. Following drying, the egg strips are cut into 1 inchsquares. One square containing no less than 10 eggs is used for eachtest compound. Initial tests are carried out at 500 ppm made from astock solution of 50,000 ppm in a DMF/isopropanol 1:3 (vol.) mixturecontaining 4% of a commercial wetting agent; the dilutent is a 70%aqueous acetone mixture.

An egg patch is placed into a Buchner funnel, attached to a vacuumsource. Ten ml. aliquots of the appropriate compound are poured directlyonto the patch. The chemical is immediately removed by suction. The eggpatch is allowed to air dry and the number of eggs per patch isrecorded. The treated eggs are then placed in a disposable petri dish(100×20 mm.) containing 30 ml. of normal looper rearing media (casein,alfalfa meal, wheat germ diet). A disc of filter paper 11 cm. indiameter is placed over the dish. The plastic lid is then pressed overthe filter paper to seal the dish, which are then incubated at 30±1degrees C. for six days.

To evaluate activity, the number of larvae emerging from each egg patchare counted. The resulting count is compared to the number of eggscontained in the patch and percent emergence is then calculated. Thecompounds were tested at concentrations of 500 and 250 ppm.

The results are shown under heading A of Table II, using the followingratings: 0-20% emergence=3; 20-50% emergence=2; 50-75% emergence=1 and75% emergence=0.

In the same fashion as above, some of the above compounds are alsotested against eggs of the Heliothis verescens (tobacco bud worm) at 500ppm and lower. The results are shown in column B, using the same ratingscale. In this test, the larvae are counted after three days instead ofthe above 6-day span.

                  TABLE II                                                        ______________________________________                                        Compound of                                                                              Test A      Test B                                                 Example No.                                                                              500     250     500   250   125 ppm                                ______________________________________                                        1          2       2       NT    NT    NT                                     3          3       3       NT    NT    NT                                     4          3       3       3     3     2                                      5          3       3       NT    NT    NT                                     8          2       1       NT    NT    NT                                     9          2       1       NT    NT    NT                                     10         2       1       NT    NT    NT                                     11         3       3       3     2     1                                      14         3       2       3     1     1                                      ______________________________________                                         NT = not tested                                                          

As seen from the above results, the compounds used for the currentprocedure are highly effective in preventing larvae development. Thisovicidal activity is of great commercial interest because of the damagethat can be caused by the hatching insects. While the above tests aredirected to specific eggs only, it will be understood that thesecompounds have ovicidal effect over a much wider variety of insect eggs;however, the above identified species are among the most difficult onesto combat and it is generally accepted that ovicides used successfullyagainst cabbage loopers and corn-ear worms are effective also incombating the hatching of eggs of other crop-damaging insects, i.e., theentire heliothis family.

As described above, the current compounds are commonly applied indiluents, preferably at a concentration of 500-2500 ppm. Wettablepowders which may optionally contain other ingredients useful incombating agricultural pests (fungicides, insecticides, etc.) areordinarily prepared by use of 0.01-0.1% by weight of a wetting agentsuch as an alkyl sulfate, an aralkyl sulfonate, a sulfosuccinate, apolyethylene glycol ether or the like. Dusting powders are made with thecurrent ovicides and a finely divided, inert diluent. In this instance,the above range of 0.05-0.25% by weight of the new ovicide is alsopreferred and again, other agricultural control agents may be includedin such a compound.

The above examples are directed to the use of the compounds per se withthe depicted structure. Their simple salts can be used in similarfashion and frequently, their preparation is easier than that of thefree compound as it allows the use of the appropriate acid in theisolation or purification steps. Among the most common acids thatfrequently add to the above bases are the hydrochloric, sulfuric,acetic, oxalic, maleic or succinic acids. Other organic acids can alsobe used but they are less economical than the above.

I claim:
 1. A method of combating the hatching of eggs of crop-damaginginsects consisting essentially in applying to the habitat of said eggsan ovicidal amount of a compound of the formula ##STR3## wherein X andY, independently, stand for hydrogen, halogen, loweralkyl,loweralkyloxy, nitro or CF₃ ; R is hydrogen or methyl; and R' ishydrogen or loweralkyl and simple acid addition salts thereof, togetherwith an agriculturally acceptable carrier.
 2. The method of claim 1wherein said ovicidal compound is present in said carrier at aconcentration of 0.05-0.25% by weight.
 3. The method of claim 1 whereinR, R' and Y are hydrogen and X is chlorine.
 4. The method of claim 3wherein said chlorine is in the 3-position.
 5. The method of claim 3wherein R and R' are hydrogen and X and Y are halogens.
 6. The method ofclaim 5 wherein said halogens are chlorines in the 3- and 4-position. 7.The method of claim 2 wherein R and R' are H, X is loweralkyl and Y ishalogen.
 8. The method of claim 7 wherein said loweralkyl is methyl inthe 2-position and said halogen is chlorine in the 4-position.